IS 1528 (Part 22) :2007 ISO 8841:1991

Indian Standard METHODS OF SAMPLING AND PHYSICAL TESTS FOR REFRACTORY MATERIALS
PART 22 METHOD FOR DETERMINATION OF PERMEABILITY TO GASES OF DENSE SHAPED REFRACTORY PRODUCTS

Ics

81.080

@ BIS 2007

BUREAU
MANAK September 2007

OF

INDIAN

STANDARDS
ZAFAR MARG

BHAVAN,

9 BAHADUR SHAH NEW DELHI 110002

Price Group 3

Refractories

Sectional

Committee,

MTD 15

NATIONAL

FOREWORD

This Indian Standard (Part 22) which is identical with ISO 8841 : 1991 `Dense, shaped refractory products -- Determination of permeability to gases' issued by the International Organization for Standardization (ISO) was adopted by the Bureau of Indian Standards on the recommendation of the Refractories Sectional Committee and approval of the Metallurgical Engineering Division Council. The text of ISO Standard has been approved as suitable for publication as an Indian Standard without deviations. Certain conventions are, however, not identical to those used in Indian Standards. Attention is particularly drawn to the following: a) Wherever the words `International be read as `Indian Standard'. Standard' appear referring to this standard, they should

b)

Comma (,) has been used as a decimal marker, while in Indian Standards, practice is to use a point (.) as the decimal marker.

the current

In this adopted standard, reference appears to certain International Standards for which Indian Standards also exist. The corresponding Indian Standards, which are to be substituted in their places, are listed below along with their degree of equivalence for the editions indicated: International ISO 6906 : 1984 reading to 0.02 mm Standard Vernier calipers Corresponding Indian Standard Degree of Equivalence Technically Equivalent do

IS 3651 (Part 2) : 1985 Specification for vernier calipers: Part 2 Vernier calipers with least count 0.02 mm (second revision) IS 1528 (Part 7) : 1974 Methods of sampling and physical tests for refractory materials: Part 7 Methods of sampling and criteria for conformity (first revision)

ISO 5022 : 1979 Shaped refractory products -- Sampling and acceptance testing

For the purpose of deciding whether a particular requirement of final value, observed or cal&lated, expressing the result of a test accordance with IS 2 : 1960 `Rules for rounding off numerical significant places retained in the rounded off value should be the in this standard.

this standard is complied with, the or analysis, shall be "rounded off in values (revised)'. The number of same as that of the specified value

IS 1528( Part22) :2007 ISO 8841:1991

Indian Standard METHODS OF SAMPLING AND PHYSICAL TESTS FOR REFRACTORY MATERIALS
PART 22 METHOD FOR DETERMINATION OF PERMEABILITY TO GASES OF DENSE SHAPED REFRACTORY PRODUCTS

1
This the

Scope
International measurement Standard of the specifies permeability a method to gases for of where

v
7

(p, + p,)
)1~'

`

A*

`h

­P2)"

*P

. . . (4)

dense, shaped refractory products.
The method specified takes account of the dyNOTE 1 the results obnamic viscosity of the gas, and therefore
tained may not be directly comparable with those obtained by earlier methods which took no account of viscosity. The determination is generally made by the passage of air. Other gases may be used when required, and the viscosities of air and nitrogen are given.

p'

is the volume of gas passing material, in cubic metres;

through

the

(

is the time, in seconds, in which that volume of gas passes through the material; is the square permeability metres; of the material, in

//

v

2

Normative reference A h

is the dynamic viscosity, in pascal seconds, of the gas at the temperature of the test; is the metres,
is

The following standard contains provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the edition indicated was valid, All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent edition of the standard indicated below. Members of IEC and ISO maintain registers of currently valid International Standards, ISO 6906:1984,

cross-sectional of the material thickness,
in

area, in traversed;
metres,

square

the

of the

ma-

terial

traversed; pressure, in pascals, of

P PI

is the absolute the gas;

is the absolute pressure, in pascals, where the gas enters the material; is the absolute pressure, in pascals, where the gas leaves the material.

Vernier callipers reading to 0,02 mm.
172

3

Definition
Standard, the

NOTES
2 Equation duced from 3 Since (1) corresponds to Darcy's the Hagen Poiseuille Law. under which Law, and is de-

For the purposes of this International following definition applies.

permeability of a material: The property by 3,1 which the material allows a gas to pass through it when under a difference of pressure.
The permeability (~) is calculated using the following equation, given for the volume of gas passing through a test piece in a given time:

p is the pressure

is measured, p = p, when pressure, and p = p2 when
pressure.

operating
operating

the volume of gas under positive
under negative

4 The factor (pI + pJ/2p is usually very close to unity and may be neglected when operating with small pressure differences, e.g. when (pl ­ p2) is less than 1000 Pa.

IS 1528 (Part 22):2007 ISO 8841:1991

Equation

(1) may

be rearranged

as

(2)
Writing equation (2) in the units involved, the unit for permeability is square metres, derived from

reading column height, meniscus error, error in the verticality of the manometer, and measurement of the density of the manometer liquid). The pressure shall be determined close to one face of the test piece in the vessel containing the test piece holder

(5.1.2).
NOTE 6 pressure
connecting

A lower pressure reading may result when the away from the test piece is determined in the
tubes.

in centimetres, A If, in equation (l), 6 is expressed in square centimetres and V in cubic centimetres (the units for the other quantities being unchanged), an alternative unit for permeability may be derived, namely square centimetres, However, since compound prefixes are not permissible, the conventional prefixes may be used only with the unit square metres, thus 10-B cm2 = 10- `2m2 = lpm2.

Gas flow measuring equipment, consisting of a sensitive floating flowmeter calibrated for a given temperature and pressure of entry. The flowmeter shall be accurate to within 2 O/.. The flowmeter shall be calibrated periodically for the gas to be used, and only the middle section of its measuring scale shall be used.
For the measurement of permeability to air only, the rate of air ffow is measured by the displacement of

5.1.4

4

Principle

air by water, using a graduated
a chronometer.

cylinder device and

A stream of dry gas is passed through the test piece, and the pressure drop across the test piece is recorded for at least three different rates of flow. From these values, and from the size and shape of the test piece, the permeability of the material is determined by calculation,

5,1.5 Vernier ISO 6906. 5.1.6 Drying

callipers,

in

accordance

with

oven,

capable

of being

controlled

at

11O"C*5"C. 5
5.f

Apparatus General

5.1,7

Impermeable

dummy test piece, for example

an aiuminium

cylinder.

The general layout of the apparatus is shown diagrammatically in figures 1 and 2. Figure 1 shows the arrangement for the passage of gas under pressure and figure 2 for the passage of gas under suction. The connecting piping shall be made of glass in preference to rubber, and shall be as short as possible, so that the pressure loss in the apparatus is very small when compared with the pressure loss produced by the test piece.

6 6.1

Test pieces Dimensions

The test pieces shall be cylindrical, with diameter 50 mm + 0,5 mm and height 50 mm * 0,5 mm. The perpendicularity of the axis of the test piece to the faces, and the paraHelism between the top and bottom faces of the test piece shall both be within 0,5 mm. NOTE 7 A 50 mm cube test piece may also be used where necessary. In this case the test piece holder (see note to 5.1.2) will need to be modified and the calculation of the results (see 8.3) will be slightly different.

5.1.1

Supply

of gas (under

pressure

or suction),
pressure.

consisting

of a reservoir

of gas at constant

5.1.2 Test piece holder, with gas-tight seals at the sides of the test piece. Gas tightness shall be ensured by a rubber membrane that is inflated to a pressure of 0,2 N/mm* to 0,4 N/mm*. See figure 3.
NOTE 5 Modifications will be required test piece size (see note to 6.1) is used. if the alternative

6.2

Preparation

5.1.3 Llquld manometer, of the U-tube type, for measuring the difference in pressure between the two faces of the test piece. The usual experimental precautions for this type of measurement shall be taken, so that the error in the pressure determination does not exceed 1 ~0 (including error in

The test pieces shall be cut in such a way that no material is included that was within 4 mm of a face of the brick or item. The direction in which the test pieces are cut, relative to the direction of pressing, shall be stated in the test report. The faces shall be freed from dust formed during the cutting, by brushing under a jet of water following wet cutting, or by a jet of compressed air following dry cutting.

2

IS 1528( Part22) :2007 ISO 8841:1991

6.3

Drying

The test pieces shall be dried to constant mass in the drying oven (5.1.6) at 110 "C + 5 `C. Before measurement, the test pieces shall be allowed to cool to room temperature in a desiccator; the time of cooling shall be at least 2 h

T d .+7
30 3b 1 1 KE'f

f.,
5

1
2 3 4 5

Sourco of gas (comweaead !rascylinder or water rear?rvoir) Desiccator;or the gas Floating flowmeters: (at O to Z30 cm3/min, (b) 200 cm3/min to 1 500 cm31 min Holder for cylindrical sample U-tube menometer, filled with liquid

For preaaura
measurement J?!

Figure 3 ­ Test piece hoider

of instruments for Figure 1 -- Arrangement measuring gas permeability (measured undera pressurehead)

7

Procedure

KEY

!L!x!7 5 5 6

1
2 3 4 5 6 7

2
\2

1

7.1 Carry out a blank determination to estabiish that the test rig is gas-tight using an impermeable dummy test piece (5.1.7) in the place of the normai test piece,

7.2 Measure the diameter and the height of the test piece to 0,1 mm, using the Vernier callipers (5.1.5). 7.3 Place the test piece in the holder (5.1.2), ensuring that the pressure on the rubber membrane is sufficient to render the cylindrical surface of the test piece gas-tight, This may be checked by increasing the pressure on the membrane; there should be no change in the pressure difference between the plane faces and no change in the rate of gas flow. 7.4 Determine the rate of flow through the test piece for at least three different pressure drops across it. Calculate the permeability of the test piece for each determination. (See clause 8.)
NOTE 8 Theee determination are to verify that the rate of ffow ie proportional to the pressure drop, because the equation ueed for the calculation (see clause 8) is only valid for Iaminar flow.

Entry of the gas, via a desiccator Holder for cylindrical eamde U-tube manometer filled &ith liquid Floating flowmeters: (a) O to 2C0 cm3/min, 1500 cm3/min Woulff safety bottles Regulating vent Diaphragm or water pump

(b) 200 cm3/min to

Figure 2 ­ Arrangement of instruments for measuring gas permeability (measured under suction)

IS 1528 (Part 22):2007 ISO 8841:1991

7.5 If the calculated permeabilities at the three different pressure drops differ among themselves by more than 5 ~0, repeat the blank test, check the equipment and repeat the tests. If the repeat tests stilt differ by more than 5 ~o, state this in the test report.

p=rl

--103
X

h

4X106

1 9,807Ap'

q' v " 60x 10%

x 104

rcd2

2,16 _--

10--2qhq"v k
(4)

d2Ap'
where

v

v

is the onds, piece

dynamic

viscosity,

in pascal

sec-

of the gas passed at the temperature height,

through the test of the test; of the test

8

Expression of results

h

is the piece;

in millimetres,

d 8.1 The permeability,
to two significant digik,

is the diameter, piece:

in millimetres,

of the test

expressed in square metres
is" given by the equation

Ap'

is the pressure difference across the test piece, in millimetres, of water columnz~; is the rate per minute,
is a correction removal

(3)

q'v

of flow, in cubic centimetres of gas through the test piece;
factor (see table 1) for the

where ~

kv
is the dynamic viscosity, onds'), of the gas passed piece at the temperature is the height, in metres, in pascal secthrough the test of the test; of the test piece;

air flow of water).

of water vapour was measured

[used only if the
by displa~ement

h

A

is the cross-sectional area, in square metres, of the test piece through which the gas has passed (see 7.2): is the pressure difference piece, in pascals; across the test

If the alternative test piece size and used (see 6.1 and 5.1.2), equation (4) will fied as follows:
8.S

holder is be modi-

Ap

.
4 x 106 -- is replaced 106 by--

ndz qv kv
is the rate of flow, in cubic metres per second, of gas through the test piece; is a correction factor (see table 1) for the removal of water vapour (used only if the air flow was measured by displacement of water), where piece. x is the Equation 1,70 X 10-

X2
side, in millimetres, (4) becomes of a cubic test

2qhq:v

kv

x2Ap'

NOTE 9 For air temperatures from t6 "C to 24 "C the values for the dynamic viscosity of air (q) are given in table 1, and these may be used under the assumption that the pressure drop over the test piece is small (see note 3 to clause 3). The values for the dynamic viscosity of nitrogen are given in table 2, from 10 `C to 35 `C.

Table 1 ­ Dynamic viscosity of air
Temperature `c Dynamic

viscosity

k,
x
10-6 Pas

16 18 20

t7,88 17,98 18,08 18,18 18,28

0,982 0,980 0,911 0,914 0,971

8.2

Equation (3) may be written

units more likely to be directly the value of the permeability, centimetres, is given by 1)
2)

in terms of the read in the test. Thus expressed in square

22 24

1 poise =O,l
1 mmH20

Pas Pa

= 9,807

4

IS 1528( Part22) :2007 ISO 8841:1991

a)

the name the date

of the testing of the test;

establishment;

Table 2 ­ Dynamic viscositv of nitrogen
Temperature "c x Dynamic viscosity 10"" E Pas 17,1 17,2 17,2 17,3 17,3 17,4 17,4 17,5 17,5 17,6 17,6 17,7 17,7 Temperature Dynamic viscosity x 10" s Pas

b) c)

`c
23 24 25 26 27 28 29
30 31 32 33 34 35

a reference "Determined

to this International in accordance with

Standard, ISO 8841";

i.e.

d)
10 11 12 13 14 15 16 17 18 19 17,7 17,8 17,8 17,9 19,9 16,0 18,0 18,1 18,1 18,2 18,2 18,2 18,3

a description of the material tested turer, type, batch number, etc.); the number of samples tested for each of gas flow in the brick or item; [he gas used; the separate pressure drops

(manufac-

e)

direction

f) 9)

(pressure

or

suction) sponding h)

across the test piece, and the correrate of gas flow through the test piece; permeability of gas flow
of the in brick

20 21
22

the mean value of the terial for each direction
the direction to of pressing any

of the ma(relative to
or item); be-

i)

Preference

variation

permeability

9
The

Test report
test report shall include the following

tween the three different determinations greater than the permitted value (see 7.5). infor-

which is 7.4 and

mation:

NOTE 10 The individual values are used for determining the mean value. The mean value is used for further statistical analysis, in accordance with the ISO 5022.

5"

Bureau

of Indian

Standards

91S is-a statutory institution established under the Bureau of Indian Standards Act, 1986 to promote harmonious development of the activities of standardiz'ation, marking and quality certification of goods and attending to connected matters in the country.
Copyright

No part of these publications may be reproduced in any 91S has the copyright of all its publications. form without the prior permission in writing of BIS. This does not preclude the free use, in course of implementing the standard, of necessary details, such as symbols and sizes, type or grade designations. Enquiries relating to copyright be addressed to the Director (Publications), 91S. Review of Indian Standards Amendments also reviewed indicates that for revision. amendments Additions'.
This Indian

are issued to standards as the need arises on the basis of comments. Standards are periodically; a standard along with amendments is reaffirmed when such review no changes are needed; if the review indicates that changes are needed, it is taken up Users of Indian Standards should ascertain that they are in possession of the latest or edition by referring to the latest issue of '91S Catalogue' and `Standards: Monthly

Standard

has been developed

from Dot: No. MTD 15 (4710). Issued Since Publication Date of Issue Text Affected

Amendments Amendment No.

BUREAU Headquarters:

OF INDIAN

STANDARDS

Manak Bhavan, 9 Bahadur Shah Zafar Marg, New Delhi 110002 Website Telephones: 23230131,23233375, 23239402 Regional Offices: Central : Manak Bhavan, 9 Bahadur Shah Zafar Marg NEW DELHI 110002 1/14, C.I.T. Scheme WI M, V.I.P. Road, Kankurgachi KOLKATA 700054 160022

www.bis.org.in Telephones 23237617 23233841 { 23378499,23378561 23378626, 23379120 2603843 { 2609285 22541216,22541442 { 22542519,22542315 $28329295, 283278!58 ~ 28327891,28327892

Eastern :

{

Northern : SCO 335-336, Sector 34-A, CHANDIGARH

Southern : C.I.T. Campus,

IV Cross Road, CHENNAI 600113

Western : Manakalaya, E9 MlDC, Marol, Andheri (East) MUMBAI 400093 Branches: AHMEDABAD. GHAZIABAD. PARWANOC).

BANGALORE. BHOPAL. BHUBANESHWAR. COIMBATORE. FARIDABAD. GUWAHATI. HYDERABAD. JAIPUR. KANPUR. LUCKNOW. NAGPUR. PATNA. PUNE. RAJKOT. `THIRUVANANTHAPURAM. VISAKHAPATNAM.

Printed at Prabhat Offset Press. New Delhi-2